Tip: Look for someone selling their grownup children’s Lego collection. I recently found a couple selling their children’s old Lego collection in Facebook Marketplace. I got an enormous bag of them for just a few bucks. It was a headache to filter out the garbage in them (small non-LEGO toys, unique pieces that were not really useful, a few mixed mega blocks, broken pieces, etc) but it was worth it, my children love them!